Let-off mechanism for looms.



' No. 63|,43o. Patented Aug. 22, |899.

c. F. PERHAM.

LET0F-F MECHANISM FR LUDMS.

(No Modei) l (Application lad Oct. 17, 1896.) 2 Sheet$ she8t I.

Q Q Qi n .95 g1 j MLIEIT DR;

No. 631,430. Patented Aug. 22, |899.

c. F. PERHAM.

LET-,OFF MECHANISM FOR LOMS.

(Application led Oct. 17, 1898.)

2 Sheets-Sheet 2,

www# l Ww@ X/mh W wf UNITED STATES l PATENT OFFICE.

CHARLES F. vPERHAM, OF LOWELL, MASSACHUSETTS.

LET-oFF M iacHiNislvl` FOR Looms.

SPECIFICATION forming part of Letters Patent No. 631,430, dated August 2.2, 189e.

i Application led October I7, 1896. Serial No. 609,187. (No model.)

ITo all whom it may concern:

Be it known that I, CHARLES FOSTER PEE-1 i HAM, of Lowell, in the county of Middlesex and State of Massachusetts, have invented certain new and useful Improvements in Let- Off Mechanism for Looms, of. which the follatter rotates at a regular rate of speed, andtherefore the picks vary and the cloth is uneven and of practically small value. Hence the invention consists in a letoff mechanism for looms in whichthe pressure of the brake mechanism varies with the thickness or diameter of the layers of the threads upon the beam, being greatest when the layers are Y thickest and least when the threads are almost expended, so that the rotation of the warp-beam is varied in accordance with the depth of the layers thereon and the same amount ofthread is let ott at all times, all as I shall now proceed to describe in detail and then point out in the claims.

Reference is to be had to the accompanying drawings, and to the letters marked thereon, forming a part of this specification, thesame letters designating the same parts or features, as the case may be, wherever they occur.

Of the drawings, Figure l represents in side elevation a portion of a loom having its warpbeam equipped with my improved let ott mechanism. Fig. 2 is a rear end elevation of the same. Fig. 3 isa section on the line 3 3 of Fig. 2. Fig. 4 shows additional means for locking the warp-beam against rotation when the reeds of the lay-beam are in engagement With the cloth.

My'invention is applicable to looms of any class or pattern and is not limited to the details ot construction illustrated upon the drawings and which I shall now proceed to describe, since it is capable of being expressed or embodied in other forms and in many diierent Ways. I have shown it as being applied to a loom having the frame co and the warp-beam b, with journals c mounted in bearings d on the frame. The Warp roll or beam has at its ends flanges e and is provided with a gearsvheel f, meshing with a pinion g on a stud-shaft 71., journaled in the frame. The said stud-shaft h is equipped with a friction or brake wheel t', with which my im-v proved brake mechanism is adapted to coact in retarding the rotation of the warp-beam as the warp-threads are being drawn there from and the work upon the loom progresses.

,7' is a long lever pivoted at k to the frame and having its upper end ,y'extending above the framework of the machine. One end of the strap Z passes around the rim of the brakeisV freed from frictional engagement with the brake-wheel, and if moved to theleft the fric tion of the strap against the wheel is increased.

Upon supports n, extending up from the frame a, is mounted a shafto, having a depending arm p and laterally and rearwardly projecting armsp, connectedqby a bar p2, constituting a feeler. The lower end of the arm p is pivoted to rod q, passing loosely through an eye g' on a bracket secured to the frame, said rod being provided with an adjustable collar q2, and between it and the eye q and around the rod q is placed a pressure-spring g3. The upper end j' of the lever] is connected to the arm p' at a distance from the shaft o of about one-third of its length by a contractile or tension spring r. The warpthreads which have been previously wound upon the warp-beam pass over the bar p2 of the feeler and from thence to the heddles and other parts of the loom. justed until the parts are in normal position and the brake-strap locks the brake-wheel If the upper endj of. the lever j is moved to the-right, the strap l The springs are ad IOO against movement. 'lhen the Warp-threads, under the tension of the cloth-roll and the take-up devices, draw upon the feeler with sulicient pressure to throw the lower end of the arm p to the rightagainst the pressure of the spring g3, and thereby allow the upper end of the lever j to move to the right far enough to decrease the frictional engagement of the brake mechanism, so that the warpbeam can slowly rotate and the threads can be drawn from it. Vhen the beam is first put on the loom, the layers of thread are so deep that the threads pass from it over the feeler at an angle greater than a right angle to the latter, where they exercise their least stress or force upon it and their greatest stress upon the bra-ke, and as they are gradually reeled oft' the diameterof the layers becomes less and less and the pressure upon the feeler is correspondingly increased as the threads approach a right angle to it. Therefore it will be seen that the friction of the strap and brake-wheel is greatest when the leverage of the threads upon the warp-beam is greatest and least when the diameter of the layers of thread upon the warp-beam is diminished, and consequently their leverage upon the beam is decreased.

The yielding connection r between the brake-lever j and the feeler-arm p is an important factor in maintaining an even pressure upon the warp. By employing a spring to connect those parts the frictional engagement of the strap with the brake-wheel may be varied as required, which would not be the case were the leverj and arm p connected by a rod or other unyielding connection. The tension of the spring increases or decreases according to the position of the arm p without actually disengaging the strap from the brake-wheel, so that the tension on the warp is correspondingly unvaried. In this way a relatively long movement of the arm p toward the lever j, which would, if the connection r were not a spring, totally release the brake-wheel, merely relieves the frictional engagement to the required extent. The said spring is relatively light, and the brake-lever is sufficiently long to exert a powerful leverage in drawing the strap about the wheel. The main pressure of the warp is borne and resisted by the spring g3, which is sufficient to normally counterbalance the spring o' also. It is evident from this explanation thatwhen the tension of the warp is sucient to compress the spring g3 the movement of the feeler-arm changes the tension of the spring r and causes the leverj to release thebrakewheel sufficiently to relieve the tension on the warp.

In addition to these features I provide means for locking the warp-beam against rotation vrhen the lay strikes the cloth, as shown in Fig. 4, to which reference may now be had. Then the reeds of the lay strike the cloth, they increase the tension on the Warpthreads, and consequently partially rotate the warp-beam, so that at the next pick the warp'- threads are loose and an irregularand uneven fabric is the result. I-Ience I employa locking-lever s, fulcrumed at s on the frame ct and having a projection S2 at its upper end to extend behind the arm p. The lower end of the lever is connected by a link with the lay-operating sword, (not shown,) so that cach time the lay is thrown forward the upper end of the lever is thrust rearward until the projection s2 engages the leverp and prevents it from yielding under the increased tension of the warp-threads,and consequently the brake mechanism remains locked to the brake-wheel and the warp-beam is prevented from unwinding. When the lay is in its inoperative position, the projection s2 is withdrawn from the lever p and the latter is free to move, as before described.

I claiml. In combination, a warp-beam under constant tension from the warp, a friction-brake mechanism for checking the rotation thereof, a pivoted feeler connected yieldingly with the brake mechanism and having a portion arranged with such relation to the warp-beam that when the beam is full the warp is at an angle to the feeler greater than a right angle, and the angle decreases as the warp is unwound.

2. In combination, a warp-beam under constant tension from the warp, a friction-brake mechanism for checking the rotation thereof, a spring-held feeler pivoted above the warp beam and connected yieldingly to the brake mechanism, said feeler having a portion over which the warp passes arranged with such relation to the warp-beam that when the beam is full the warp between the feeler and the beam is at an angle to the feeler greater than a right angle and the angle decreases as the warp is unwound.

3 Inaloom, the combination with the warpbeam, and a friction-brake for the beam, of a lever for operating the brake, a laterallyextending feeler journaled in supports, and in the path of the Warp-threads, said feeler being arranged above the warp-beam, and having a depending arm, aspring connection between the said arm and the said lever, and a spring bearing against said arm against the stress of the spring connection.

4. In combination with a warp-beam, and a friction-brake therefor, of a lever for operating the brake, a feeler journaled in the path of the warp-threads, having a depending arm, yielding connections between the arm and the said lever, and means coacting with the lay for engaging the said depending arm and holding it against motion.

5. In combination with a warp-beam, and a friction-brake therefor, of a lever for operating the brake, a feeler journaled in the path of the warp-threads, having a depending arm, yielding connections between the arm and the said lever, and a pivoted lever connected with the lay and arranged to intermittingly p eiA 3 engage the depending arm, for the purpose I nected to the end of said arm and' arranged described. p to act against the first said spring.

6. Inaloom in combination,awarpbealn,a In testimony whereof I have signed my brake mechanism therefor, an upwardly-proname to this specification, in the presence of I5' 5 jecting lever for operating the brakestrap,a two subscribing witnesses, this 28th day of feeler pivoted above the Warp-beam and ar-v September, A. D. 1896. ranged to move in accordance with the varyl ing tension of the Warp, and having a rigid CHARLES F PERHAM' downwardly-projecting arm, a contractile Witnesses: Io spring connecting the end of the brake-lever HORACE BROWN, with the feeler-arm, and a tension-spring con- A. D. HARRISON. 

